GNU bug report logs - #9329
24.0.50; `condition-case' with (debug...) is broken

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 9329 in the body.
You can then email your comments to 9329 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: "Drew Adams" <drew.adams <at> oracle.com>
To: <bug-gnu-emacs <at> gnu.org>
Subject: 24.0.50; `condition-case' with (debug...) is broken
Date: Thu, 18 Aug 2011 20:47:57 -0700

(let ((debug-on-error  t)
      (eval-expression-debug-on-error  t))
  (condition-case nil (/ 1 0)
    ((debug error) "Test")))
 
The debugger is not opened.  In Emacs 23.3 it is opened (as the doc says
it should be).
 

In GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600)
 of 2011-08-15 on 3249CTO
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.5) --no-opt'
 

Message #8 received at 9329 <at> debbugs.gnu.org (full text, mbox):

From: Lars Magne Ingebrigtsen <larsi <at> gnus.org>
To: "Drew Adams" <drew.adams <at> oracle.com>
Cc: 9329 <at> debbugs.gnu.org
Subject: Re: bug#9329: 24.0.50; `condition-case' with (debug...) is broken
Date: Fri, 19 Aug 2011 14:32:47 +0200

"Drew Adams" <drew.adams <at> oracle.com> writes:

> (let ((debug-on-error  t)
>       (eval-expression-debug-on-error  t))
>   (condition-case nil (/ 1 0)
>     ((debug error) "Test")))
>
> The debugger is not opened.  In Emacs 23.3 it is opened (as the doc says
> it should be).

---
The car of a handler may be a list of condition names
instead of a single condition name.  Then it handles all of them.
---

So it seems to be doing what it's supposed to be doing.

Is this what you wanted to say instead?

(condition-case error
    (/ 1 0)
  (error
   (debug error)
   "Test"))

-- 
(domestic pets only, the antidote for overdose, milk.)
  bloggy blog http://lars.ingebrigtsen.no/

Message #11 received at 9329 <at> debbugs.gnu.org (full text, mbox):

From: "Drew Adams" <drew.adams <at> oracle.com>
To: "'Lars Magne Ingebrigtsen'" <larsi <at> gnus.org>
Cc: 9329 <at> debbugs.gnu.org
Subject: RE: bug#9329: 24.0.50; `condition-case' with (debug...) is broken
Date: Fri, 19 Aug 2011 06:18:16 -0700

> > (let ((debug-on-error  t)
> >       (eval-expression-debug-on-error  t))
> >   (condition-case nil (/ 1 0)
> >     ((debug error) "Test")))
> >
> > The debugger is not opened.  In Emacs 23.3 it is opened (as 
> > the doc says it should be).
> 
> The car of a handler may be a list of condition names
> instead of a single condition name.  Then it handles all of them.

Yes. So? (debug error) is a list of condition names.  It is the car of a handler
(the only handler).

> So it seems to be doing what it's supposed to be doing.

No.  Check the doc.  Check Emacs 23 - e.g., 23.3.1.

> Is this what you wanted to say instead?
> (condition-case error
>     (/ 1 0)
>   (error (debug error) "Test"))

No.

C-h i, Elisp, g handling errors

"If an error is handled by some `condition-case' form, this
ordinarily prevents the debugger from being run, even if
`debug-on-error' says this error should invoke the debugger.

If you want to be able to debug errors that are caught by a
`condition-case', set the variable `debug-on-signal' to a non-`nil'
value.  You can also specify that a particular handler should let the
debugger run first, by writing `debug' among the conditions, like this:

     (condition-case nil
         (delete-file filename)
       ((debug error) nil))
"

Put the cursor after that sexp.  `C-x C-e'.  Do the same thing in Emacs 23.

Message #14 received at 9329 <at> debbugs.gnu.org (full text, mbox):

From: Chong Yidong <cyd <at> stupidchicken.com>
To: "Drew Adams" <drew.adams <at> oracle.com>
Cc: 9329 <at> debbugs.gnu.org
Subject: Re: bug#9329: 24.0.50; `condition-case' with (debug...) is broken
Date: Sat, 20 Aug 2011 17:17:11 -0400

"Drew Adams" <drew.adams <at> oracle.com> writes:

> (let ((debug-on-error  t)
>       (eval-expression-debug-on-error  t))
>   (condition-case nil (/ 1 0)
>     ((debug error) "Test")))
>
> The debugger is not opened.  In Emacs 23.3 it is opened (as the doc says
> it should be).

Thanks.  This regression was due to the 2011-01-26 change to eval.c on
the trunk (r102982).  I've committed a fix.

Message #19 received at 9329 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
To: Chong Yidong <cyd <at> stupidchicken.com>
Cc: 9329 <at> debbugs.gnu.org, Drew Adams <drew.adams <at> oracle.com>
Subject: Re: bug#9329: 24.0.50; `condition-case' with (debug...) is broken
Date: Sat, 20 Aug 2011 23:50:40 -0400

>> (let ((debug-on-error  t)
>> (eval-expression-debug-on-error  t))
>> (condition-case nil (/ 1 0)
>> ((debug error) "Test")))
>> The debugger is not opened.  In Emacs 23.3 it is opened (as the doc says
>> it should be).
> Thanks.  This regression was due to the 2011-01-26 change to eval.c on
> the trunk (r102982).

Indeed I hate this "feature" and didn't bother to reimplement it.

> I've committed a fix.

Oh well,


        Stefan

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.